Senate Majority Leader Mitch McConnell, R-Ky., and a top deputy are planning to help Sen. Luther Strange raise money this week for his closely watched primary runoff - even as Strange sides with President Donald Trump over McConnell when it comes to a venerated Senate rule.

As McConnell gears up to help Strange during the last stretch of his heated contest, Strange announced Tuesday that after previously supporting the preservation of the Senate's 60-vote threshold on most legislation, he agrees with Trump that it should be ended.

McConnell is scheduled to appear at a high-dollar fundraiser on Thursday in Washington to benefit Strange, according to an invitation shared with The Washington Post by a person familiar with the event.

Individuals are encouraged to give as much as $2,000 and political action committees are being asked for as much as $5,000, according to the invitation, which was shared by the person on the condition of anonymity to describe a gathering that was not widely publicized.

Sen. John Thune, S.D., the third-ranking Republican senator, is slated to appear at a Tuesday evening dinner fundraiser for Strange in Washington, where top donations will range from $1,000 to $2,500, according to an invitation provided by the person.

A second Republican familiar with the events confirmed both of them. Strange's campaign did not offer any comment. Representatives for McConnell and Thune did not comment on the plans.

McConnell has long supported Strange, who recent polls show is in a competitive race. Strange has struggled to solidify the support of his state's conservative base, even as he has aligned himself closely with Trump. He took another step closer to the president Tuesday when he announced his support for ending the 60-vote threshold, as Trump has repeatedly advocated.

"While I had hoped that Republicans and Democrats would work together to accomplish the will of the American people, it has become obvious that politics and self-preservation will continue to rule the day," Strange said in a statement announcing his decision. "Conversations with the President have led me to the conclusion that changing the filibuster rule is the only way we will be able to build the border wall, rein in sanctuary cities, defund Planned Parenthood, and give the American people real tax relief."

McConnell does not support ending the 60-vote threshold and has vowed to protect it as majority leader.

McConnell and his allies are hoping to boost Strange across the finish line in the race for the seat vacated by now-Attorney General Jeff Sessions earlier this year. Strange placed second last month in the first round of voting to former judge Roy Moore, a hard-right conservative who has openly attacked McConnell. The runoff between the top two candidates will be held Sept. 26.

Trump also backs Strange. He tweeted his support and recorded a robo-call ahead of the August vote. But he has weighed turning his focus away from the contest.

If Trump does decline to become more deeply involved, it would be a blow to Strange, because the president is very popular in the state. Strange's support for ending the legislative filibuster underscored the strength of Trump and his positions in Alabama, where he won the primary and general elections last year by a wide margin.

Strange, who was state attorney general, was appointed to the Senate after Sessions's departure by then-Gov. Robert Bentley, a Republican. The winner of the Republican primary will face the Democratic nominee, former U.S. attorney Doug Jones, on Dec. 12.